Preparation of organophosphorus polymers by reacting a phosphorus oxyhalide with a glycol



Jan. 17, 1967 GRAMS OF PRODUCT L. FIERCE PREPARATION OF ORGANO PHOSPHORUS POLYMERS BY REACTING A PHOSPHORUS OXYHALIDE WITH A GLYCOL Filed Dec. .12, 1965 MOLES OF DIETHYLENE GLYCOL PER MOLE OF POCI INVENTOR.

WILLIAM L. PIERCE ATTORN United States Patent 3,298,968 PREPARATHUN fill URGANQEPHOSPHQRUS PGlLY- MERS BY REACTHNG A PHGSPHORUS OXY- HALIDE WITH A GLYCGL Wiiliam L. Fierce, Crystal Lake, lll., assignor, by mesne assignments, to Union Oil Company of California, Los Angeles, Calif., a corporation of California Filed Dec. 12, 1963. Ser. No. 330,083 9 Claims. (Cl. 260-2) This invention relates to an improved method for preparing rubber-like polymers by the reaction of a phosphorus oxyhalide and straight-chain glycols of molecular weight between 100 and 2000 having terminal hydroxyl groups. 7 p

The preparation of phosphate esters is well known in the art. Phosphate esters are usually prepared by reaction of an alcohol with phosphorus oxychloride (POCl usually in the presence of a basic catalyst such as pyridine. The reaction of phosphorus oxychloride with alkylene oxide polymers and with very high molecular weight poly-- ethylene glycols is also known. Harman and Vaughn in U.S. Fatent 2,536,685 report the reaction of alkylene oxide polymers with PCl or POCl at about 170 C. to produce liquids containing phosphorus and chlorine, which could be used as lubricants. Livengood in U.S. Patent 2,567,076 reports the reaction of POClwith polyethylene glycols having an average molecular weight of more than 4,000, to produce waxy solids which are water-soluble. Smith and Knoth disclose in U.S. Patent 2,632,767 that complex phosphate esters which are suitable for use as synthetic lubricants can be prepared by reacting two molecular proportions of phophorus oxychloride with one molecular proportion of a glycol and reacting the partial ester thus formed with four molecular proportions of a monohydric alcohol. Experimental work has shown that ethylene glycol and 1,2-propylene glycol react with phosphorus oxychloride to produce water-soluble liquids. Poly-1,2-propylene glycols, having average molecular weights of about 425 and 1025, respectively, react with phosphorus oxychloride to give viscous, ether-soluble liquids.

It is reported in U.S. Patent 3,013,991 that rubbery organophosphorus polymers are prepared by reacting a phosphorus oxyhalide in a 1:3 mol ratio with an aliphatic straight-chain glycol, having terminal hydroxyl groups and a molecular weight less than about 2000, in a non-aqueous, inert solvent at 10 to C. Based upon elemental analysis of the organophosphorus polymer produced by the reaction of phosphorus oxychloride and diethylene glycol, as for example, the polymer is probably a crosslinked phosphate having a structure similar to that indicated below:

The rubber solids produced in accordance with the process described in U.S. Patent 3,013,991 are very inert, are

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insoluble in solvents such as water, dilute acids, ketones, others, alcohols and hydrocarbons, and melt, with decomposition, above 200 C.

This invention is based on the discovery that the organophosphorus polymers of U.S. Patent 3,013,991 are prepared appreciably increased yields by combining the reactants so that the aliphatic straight-chain glycol is added to the phosphorus oxyhalide and using an excess of the aliphatic straight-chain glycol is added to the phosphorus oxyhalide and using an excess of the aliphatic straightchain glycol in a glycol: phosphorus oxyhalide mol ratio of less than 3:1.. i

It is therefore the primary object of this invention to provide an improved method for preparing rubbery organophosphorus polymers. Another object of this invention is to provide a method for preparing rubbery or ganophosphorus polymers wherein the method of combining the reactants and mol ratios of the reactants are critical. Other objects of this invention will become apparent from time to time throughout the specification and claims as hereinafter related.

In accordance with this invention, appreciably increased yields of the organophosphorus polymers are obtained by reacting a phosphorus oxyhalide with an aliphatic straightchain glycol, having terminal hydroxyl groups and a molecular weight less than about 2000, in a mol ratio of about 1:15 to 1:25 at about l0 to +20 C. in a nonaqueous inert solvent, the aliphatic straight-chain glycol being added to the phosphorus oxyhalide. Reaction temperatures from about 0 to +10 C, are preferred.

In the process of making these rubbery polymers, any phosphorus oxyhalide, such as phosphorus oxybromide or phosphorus oxychloride, may be used, although the chloride is preferred.

The reactant glycols which are included in the term aliphatic straight-chain glycols are the straight-chain a,w-alkanediols[HO(CH OH, where x is 3 to 24] and condensed straight-chain polymers of straight-chain saw,- alkanediols, having the general formula 2)x )n where x is a small integer (e.g., 2-12) and n is a small integer (2 or more) dependent upon size of x, of a value such that the molecular weight of the compound does not exceed about 2000. Polyethylene glycols are preferred in the production of these rubbery polymers and have the formula HO(C H O) l-l, where n is an integer from about 2 to 45. Polyethylene glycols which may be used include diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and all other glycols of the general formula given, including mixtures thereof in all proportions. Alkanediols which may be used include a,w-C -C straight-chain alkanediols, such as trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, pentadecamethylene glycol, and 1,20-eicosanediol.

The reaction is preferably carried out in an inert nonaqueous solvent (inert toward the reactants and reaction products) such as dirnethyl ether, diethyl ether, carbon tetrachloride, trichloroethylene, toluene, hexane, or dimethyl phthalate. The reaction proceeds best in the presence of an amine (HCl acceptor) such as pyridine, quinoline, a dialkylaniline, e.g., N,N-dimethylaniline, N- methyl-Nethylaniline, N,N-diethylaniline, N-methyl-N propylaniline, etc., or a trialkylamine, e.g., trimethylamine, triethylamine, tributylamine, N,N-diethylmethylamine, N-ethyl-N-methylpropylamine, etc. The amine is used in an amount sufficient to combine with the by-product HCl expected to be produced in the reaction. A slight excess of the amine is preferably used. The amine may be added to the phosphorus oxyhalide, the glycol, or even the phosphorus oxyhalide-glycol mixture.

EXAMPLE I A round-bottom flask equipped with a condenser, thermometer, stirrer, dropping funnel and a cooling bath was charged with 51.1 grams mol) of phosphorus oxychloride dissolved in 500 ml. of anhydrous ether. The dropping funnel was charged with 70.8 grams (3,; mol) of diethylene glycol dissolved in 75 ml. of anhydrous ether.

glycol: phosphorus oxychloride mol ratio within the range of about 1.511 to 2.5:1 is used rather than 3:1.

EXAMPLE II In another experiment a reaction was carried out in the identical manner described in Example I except that 51.1 grams mol) of phosphorus oxychloride dissolved in 75 ml. of anhydrous ether was added to a mixture of 85 ml. of pyridine and 106.1 grams (1.0 mol) of diethylene glycol dissolved in 250 ml. of anhydrous ether. The

Eighty-five ml. (1.05 mol) of pyridine was added to the White, rubbery product which was obtained had a melting solution in the dropping funnel. After the contents of point (with decomposition) of 275 C. and an elemental the flask were cooled to 10 C., the mixture in the dropanalysis of 35.1% carbon, 6.5% hydrogen, 0.6% chloping funnel was slowly added with stirring. The temrine, and 8.8% phosphorus. This product which was perature was held near 10 C. and the addition time was apparently the same as the products of Example I, was about two hours. The reaction mixture was then allowed obtained in a yield of 7.8 grams, demonstrating the reto warm to room temperature. A white, somewhat granduced yields which are obtained when the order of adding ular, solid product precipitated from the solution and the reactants is reversed. was removed by filtration. The product was washed with dilute HCl and water, dried, and weighed. The yield EXAMPLE HI f h product was 4 granm hi product was b- In still another experiment a reaction was carried out b d i l bl or b t ti ll i l bl i common in the identical manner described in the first run of Exsolvents such as water, dilute acid, acetone, ether, toluene, ample I except that the Ifiactioh temperathhe Was held n-heptene, Xylene, methyl isobutyl ketone, tetrahydrohear A White rubber-like Solid Which Was pfuran, ethylacetate, carbon disulfide, acetonitrile, 22- 25 p h y the Same as ths Products of -P I Was ethoxyethanol, dimethylsulfoxide, 2-propanol, furfural, Ohtalhed in a yield of 222 gmlhs- The Solid had a and dimethylforma'mide. The product was almost commelting P0111t (With dficompositioh) of pletely dissolved by 5. 0 N sodium hydroxide. Th b- This experiment clearly points out the reduced product h nature f hi product, together i h i l k f yields which are obtained when temperatures higher than solubility in a known solvent, made it practically imposthe Preffirred temperatures are usedsible to determine the molecular structure. Because of EXAMPLE IV the lack of solubihty, and the rubbery character of the product, it was presumed to be of polymeric nature. The When phosphonls oxychlonde and dlethylene glycol product was further characterized by amelting point (with am reacted as Outhned for the fi run of Example decomposition) of about The elemental anai except that Chlorothene (1,1,1-tr1chloroethane) was used ysis of this product was carbon 344% hydrogen 63% as a solvent, apolyrner formed, but It could not be easlly chlorine 11%, and phosphorus This analysis isolated slnce it formed a stable gel when water-washed. does not correspond to any simple compound which EXAMPLE V could be produced by this reaction, and is believed to When phosphorus oxybromiide and diethylene glycol further substantiate the presumed polymeric nature of 4.0 are reacted in the manner outlined for the first run of the product Example I, a rubber-like polymer having properties sirni- Four more runs were conducted 1n the identical manner iar to the products of Example I iS Obtained. described above except for the var1at1on 1n the amount of diethylene glycol used. The results of these experi- EXAMPLE VI ments are set forth in Table I and are graphically pre- When the procedure outlined for the first run of Exsented in the accompanying drawing. ample I is repeated, using triethylene glycol in the same TABLE I Amounts of Reactants Used Amount of Pyridine Polymer Run Diethylene Phosphorous Used Glycol/POCl Yield, Glycol Oxychloride Moi Ratio Grams Grams Mols Grams Mols Ml. Mols 2 35.4 s 51.1 is 85 1.05 1.0/1.0 15.4 3 53.1 it 51.1 t. 85 1. 05 1.5/1.0 36.4. 4 88.4 at 51.1 s 85' 1. 05 2.5/1.0 48.3 5 106.1 1 51.1 s s5 1.05 3.0/1.0 20.0

From these data it is seen that the polymer yield varied molar ratio as the diethylene glycol of Example I, a appreciably as diiierent diethlyene glycol: phosphorus White rubbery solid having properties similar to the prodoxychloride mol ratios were utilized, with the maximum nets of Example I is obtained. yield being obtained when a diethylene glycolzphosphorus oxychloride mol ratio of about 2:1 was used, as described 05 EXAMPLE VII i h fi t run h h polymer i ld i l t d Several experiments were run in which a mixture of against diethylene =glycol:phosphorus oxychloride mol polyethylene glycol 400 dissolved in anhydrous ether ratio, as shown in the accompanying drawing, it appears and pyridine were slowly added to phosphorus oxychloas if the maximum polymer yield is obtained when a ride dissolved in anhydrous ethef- Polyethylene E i diethylene glycoliphosphorus oxychloridemol ratio within 400 is a Comm rcial product Obtained from Union Carthe range of about 2.0:1 to 2.25:1 is used. Although i Chemicals Company, and is a mixture of polyethylthe exact peak of the curve (as represented 'by the dashed e116 g y having an average molecular Weight of about portion) is unknown, it would appear from the data that 400 and Containing Polyethylene glycols ranging from the maxi um yield i obt ined by in l ti ithi tetraethylene glycol up to pentadecaethylene glycol, with this range. In any event, it will be apparent that the octaethylene glycol, nonaethylene glycol, decaethylene polymer yield is appreciably greater when a diethylene glycol, hendecaethylene glycol, and dodecaethylene glycol predominating. Glycol; phosphorus oxychloride, mol ratios ranging from 1:1 to 2:1 and reaction temperatures ranging from to 25 C. were used in these runs. In each run a solid product formed which gelled in contact with water and could not be washed and purified.

The rubber-like or-ganophosphorus polymers produced in this invention have a variety of uses. These materials, because of their chemical inertness and lack of solubility in common solvents, may be used as fillers, packings, and absorbents for chemical reactors. These products in granulated form may be used as filter-aids for filter presses. The elasticity and high chemical and thermal stability of these polymers make it possible to substitute them for rubber and other elastic polymers for padding in upholstered furniture. These products may be finely granulated and incorporated in a paint base as a fire-retardant filler.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a process of preparing rubbery organophosphorus polymers by reacting a phosphorus oxyhalide with a glycol in the presence of an amine, selected from the group consisting of pyridine, quinoline, dialkylanilines and trialkylamines, in an inert, non-aqueous solvent at a temperature of about 10 C. to --|-20 C., said glycol being selected from the group consisting of polyethylene glycols of the formula HO(C H O) H, where n is 2 to 45, and a,w-C -C straight-chain alkanediols, and recovering as a solid precipitate the reaction product consisting of a rubbery solid characterized by its insolubility in water,

dilute acids, ketones, ether, alcohols, and hydrocarbons, and melting, with decomposition, at a temperature above 200 C., the improvement which comprises gradually adding said glycol to said phosphorus oxyhalide in the order indicated over an extended period and using a glycolzphosphor-us oxyhalide mol ratio within the range of about 1.511 to 25:1.

2. A process according to claim 1 in which the phosphorus oxyhalide is phosphorus oxybromide.

3. A process according to claim 1 in which the glycol is a polyethylene glycol.

4. A process according to claim 1 in which the glycol is triethylene glycol.

S. A process according to claim 1 in which the phosphorus oxyhalide is phosphorus oxychloride.

6. A process according to claim 5 in which the glycol is diethylene glycol.

7. A process according to claim 6 in which the phosphorus oxych'loride and diethylene glycol are reacted in the presence of pyridine.

8. A process according to claim 7 in which a glycol: phosphorus oxychloride mol ratio in the range of about 2.0:1 to 2.25:1 is used.

9. A process according to claim 8 in which a glycol; phosphorus oxychloride rnol ratio of about 2.0:1 is used.

References Cited by the Examiner UNITED STATES PATENTS 2,567,076 9/ 1951 Livengood 260- 3,013,991 12/1961 Fierce et a1. 2602 SAMU-EL H. BLECH, Primary Examiner. 

1. IN A PROCESS OF PREPARING RUBBERY ORGANOPHOSPHORUS POLYMERS BY REACTING A PHOSPHORUS OXYHALIDE WITH A GLYCOL IN THE PRESENCE OF AN AMINE, SELECTED FROM THE GROUP CONSISTING OF PYRIDINE, QUINOLINE,DIALKYLANILINES AND TRIALKYLAMINES, IN AN INERT, NON-AQUEOUS SOLVENT AT A TEMPERATURE OF ABOUT -10*C. TO +20., SAID GLYCOL BEING SELECTED FROM THE GROUP CONSISTING OF POLYETHYLENE GLYCOLS OF THE FORMUAL HO(C2H4O)NH, WHERE N IS 2 TO 45, AND A,W-C3-C24 STRAIGHT-CHAIN ALKANEDIOLS, AND RECOVERING AS A SOLID PRECIPITATE THE REACTION PRODUCT CONSISTING OF A RUBBERY SOLID CHARACTERIZED BY ITS INSOLUBILITY IN WATER, DILUTE ACIDS, KEOTNES, ETHER, ALCOHOLS, AND HYDROCARBONS, AND MELTING, WITH DECOMPOSITION, AT A TEMPERATURE ABOVE 200*C., THE IMPROVEMENT WHICH COMPRISES GRADUALLY ADDING SAID GLYCOL TO SAID PHOSPHOROUS OXYHALIDE IN THE ORDER INDICATED OVER AN EXTENDED PERIOD AND USING A GLYCOL:PHOSPHORUS OXYHALIDE MOL RATIO WITHIN THE RANGE OF ABOUT 1.5:1 TO 2.5:1. 